Google'sHangoutsMayOfferSMSMessagingAfterAll

Google's Hangouts, the cross-platform messaging service that launched earlier this week at Google I/O, has one noticeable omission: it doesn’t support SMS. However, this could be temporary. Considered a worthy challenger to Apple’s iMessage tool, Hangouts is available on multiple platforms, including iOS and Android, as well as on the Web.
When the new service was announced at Google I/O, SMS support wasn’t mentioned, nor was it offered. However, Google did leave a little bit of news on this subject in the Google Play store.
The Hangout for Android permissions state:

READ YOUR TEXT MESSAGES (SMS OR MMS)
Allows the app to read SMS messages stored on your device or SIM card. This allows the app to read all SMS messages, regardless of content or confidentiality.
SEND SMS MESSAGES
Allows the app to send SMS messages. This may result in unexpected charges. Malicious apps may cost you money by sending messages without your confirmation.